Depends on what you mean by "say"; if you mean gender I think is true. But if you consider people who like just one music genre and can stay motivated and loyal only because of that then you don't have too much say about who will be your fans, if you like trash metal it doesn't matter if you have a PHD from Harvard and your social circle is mostly composed by honored students, because the genre you may appel to a very wide range of people for which you have little to none control (unless you are wealthy and can create your own music label, gigs scenary and location, publicity and media exposure in general.